Clustering of cases of mycobacterium fortuitum infection investigated by molecular typing

Organisms of the Mycobacterium fortuitum complex are recognized, but uncommon, causes of pulmonary disease, primary cutaneous disease and a wide spectrum of nosocomial infections. M.fortuitum was isolated from 20 patients over a 15-month period, with an apparent clustering of isolates of M.fortuitum occurring from January to March 1994. The molecular epidemiology of this clustering was investigated using an arbitrary primer-polymerase chain reaction method (AP-PCR). Twenty-two isolates were studied and yielded 14 distinct profiles. Multiple isolates from a single patient yielded identical profiles. All of seven isolates of M.fortuitum recovered during the six-weeks period from January to March 1994 shared a common profile which was distinct from all other isolates, suggesting that a single strain was located from specimens from all seven patients. The source of the cluster of isolates of M.fortuitum is uncertain. We can find no epidemiological link upon which to suppose an episode of cross-infection within the hospital environment. Therefore it seems likely that contamination of the specimens during collection, transport or processing was responsible for the "pseudo-outbreak" of M.fortuitum observed in this study (AU)

Dual intradermal testing of Barbadian children with tuberculin and battey bacillus antigen

Nine hundred and eight Barbadian children aged 4 to 8 years were tested simultaneously by intradermal injection of 0.05 g standard tuberculin (PPD-S) and an extract of Mycobacterium intracellulare (Battey bacillus) (PPD-B). Of the total number of children tested, 21.8 percent reacted to both antigens. The reaction to PPD-S was significant in 2.6 percent and to PPD-B in 13.4 percent. In 5.9 percent of the children who reacted to one or both antigens the reactions were of equal size; the reaction to PPD-S was larger in 17.4 percent and to PPD-B in 76 percent. It is concluded that the infection atypical mycobateria is not uncommon in Barbados and that a large number of moderate and reactions to tuberculin are the result of atypical infection. There is evidence that atypical mycobaterial infection protects againsts infection with M. tuberculosis and vice versa. No tuberculous infection was found in the children under four years of age. In the 4 to 5, to 6 to 7 and 7 to 8-year age groups, the age specific infection rates were respectively 1.8 percent, 4.7 percent and 4.6 percent. It is concluded that the policy of administering BCG vaccine to children of 5 years of age should be continued. There is some indication that a number of cases of tuberculosis in Barbados are either not being diagnosed or not being reported (AU)